Process of mercerizing.



NITED STATES PATENT FFICE.

PROCESS OF MERCERIZING.

5PECIFICATION forming part of Letters Patent No. 677,450, datedJuly 2, 1901. Application filed April 29, 1899. Serial No. 715,052. (Specimens) T0 aZZ whont it may concern:

Be it known that we, FERNAND GRQS and PAUL BOURCART, spinners, of Remiremont, Vosges, France, have invented certain new and useful Improvements in a New Method of Treating Cotton to Give it the Glossy Appearance of Silk; and we do herebydeclare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to a new method of treating cotton to give it the glossy appearance of silk; and the object of it is to enable yarn or the unspun fibrous spinning material to be successfully mercerized.

It may be well before proceeding with the description of our invention to explain that mercerizing is a term now generally used to designate the series of operations having for their object to impart to cotton a silk-like gloss or sheen.

An important factor in the mercerization of cotton is that the material under treatment must be stretched quite taut or subjected to considerable tension in order to counteract the shrinkage that would otherwise take place.

It has been found in practice that the gloss given to cotton by mercerization becomes more silky in proportion as the chemical solution employed is more-concentrated, and as the ensuing shrinkage is also more considerable in proportion the counteracting tension to which the fiber or material must be subjectedhastobeincreasedaccordingly. Hence although excellent results have been obtained by treating already-woven fabrics and finished or spun thread by this said process the same cannot be said of the unspun fibrous spinning material or yarn in the form of sliver, for example, owing to the fact that the latter, having practically no twist, has not the strength necessary to enable it to withstand the tension to which it would have to be submitted in being treated in a sufficiently-concentrated bath to produce the fine silky appearance desired. Besides, the innumerable free or stray ends of such cotton fiber which project laterally from the exterior surface thereof and form what is called the down escape the tension altogether, and consequently fail to acquire the gloss. In fact,

they contract and form a sort of sheath around the material, which, being dull and woolly in appearance, would greatly modify even such gloss as might have been imparted to a single fiber properly finished, (mercerized) The process which accomplishes the object of the present invention consists in mercerizing the cotton at one of the stages in the preparation of the cotton fiber or construction of the thread preparatory to the actual spinningoperation in order to obtain mercerized cotton spinning material which may subsequently be finished as ordinary spinning material, according to the stage at which the preparation was arrested and the merceriza tion begun, or, on the other hand, it maybe restored to any of its more primitive states or even converted into cotton-wool. For example, supposing the preparation of the spinning material is arrested on the completion of the drawing operation, then after the mercerization the sliver may be subjected to slubbing either once or twice, roving, spinning, and doubling to produce a thread of any thickness or size desired.

What characterizes cotton when in the condition known in spinning as prepared cottonsay in slivers as produced by carding or combing machines or in slubs or rovings produced by drawing-framesis that the fibers are assembled together with little or no twisting, so that each fiber is apt to vary its position relatively to that of the others bya sliding or slipping motion. In this state the'prepared cotton will break asunder at the slightest pull. The individual fibers, too, are comparatively short, and to subject them to the silkening process in this condition it would be necessary to stretch each of them singly, asit were, and for very smalllengths and that without breaking the continuity of the strand or sliver, and it does not seem practicable to attain this result except, perhaps, by very special and exceedingly-complicated machinery, which is undesirable for obvious reasons. Now to remedy this defect we propose to bring the cotton temporarily into a certain transitory condition by two operations, which at this stage of the spinning process would at first sight appear to be quite uncalled for, and it would be so were it not for the specific object which they enable us to accomplish.

lVe proceed as follows: The cotton in the form of either a carding, drawing, slubbing, or roving sliver, whichever the stage at which it is taken in hand, is twisted as much as is necessary to impart to the cord thus produced as much. strength as it requires to be capable of withstanding the tension, which shrinking tendency, owing to its immersion into the concentrated baths, renders imperative. As will be remembered, concentrated baths alone give the material the desired degree of silky gloss or sheen. In this preparatory' twisting process the conditions of elasticity and the other qualities which cotton yarn is generally required to combine may be disregarded, and it is for this reason that we have selected the above term cord to designat'e the special and transitory state in which the cotton is at the time, being in the state of more or less incomplete yarn, whereas the cotton, while not possessing simply the properties of the prepared material or sliver, yethas acquired and only needs a part of those of yarn or thread. The cord thusprodu'ce'd is then mercerized' by any well-known process, whereupon it is washed, acid-'ulated, rin's'ed, and lastly dried. Also either before or after drying it may be bleached or dyed. At-

ter having thus submitted the cotton cord to all th'enecessary operations we bring the fiber intoa condition in which it shall be capable'of undergoing the whole or part of the spinning processes. To this end we now untw'ist it't'o any extent that may be desirablein' fact, en'- tire'ly, if required. The mercerized cotton,

which may ha'vealso been previously bleached or dyed-, isnow restored to the condition of" pre'pared cotton, in which the fibers are parallel and'held together by more or less slight twisting, so that it can undergo the subsequent spinning operations required to convert it into yarn or thread of any given thickness, or by simply loosening (deviling) the cotton it might be restored to the condi tion of cotton-wool and'snbjected to all stages of dthe spinning process from beginning to en It-will be understood that cotton yarn or thread thus obtained possesses a fine silky gloss for two reasons-win, first,rbecause in the condition of cord the assemblage of cotton fiber offers as much resistance as is necessary to enable it to withstand the stretching strain it undergoes in the concentrated baths, which alone, as above stated, are capable of producing the desired high degree of sheen, and, second, because the down, which exists around the cord and which escapes the stretching and also, therefore, the mercerizing reaction, is during the subsequent spinning operations closely mixed with the fiber that has acquired the silky appearance.

In reality, then, our invention mainly consists in temporarily interrupting the spinning operations-, be it at the stage of treatment in the spindle-frame or in the carding, combing, drawing, slubbing, or rovingmachine, and at this stage we convert the-prepared cott'on by twisting it as 1n uch as may be necessary into cords of sufficient strength to permit them to bear the required tension during the mercerizing, and after this treatment we obliterate the whole or part ofthe twisted effect thus produced by restoring the material either to its initial state of cottonwool or to a state approaching that in which it was when the spinning process was interrupted.

To claim The process for imparting to cotton the glossy appearance of silk, characterized by first twisting the unspun material when'i'n the state of a sliver into a cord of j ust s n-flicient strength to withstand merce'rization',

then stretching such cord taut,-then submitting it -to the mercerization process;- after which the cordis nnt wisted or restoredto the state in which itwas priorto such treatment.

In witness whereof we have" hereunto set our hands in presence of two witnesses.

FERNAND eRos; PAUL BOURCA-RT.

\Vitnesses:

EMILE BERT, S12, EDW'A-RD P. lvIAoLEAN. 

